Paint vehicle with fungicidal properties



PAINT VEHICLE WITH FUNGICIDAL PROPERTIES 3, 1956, Ser. No. applicationSept. 2, 1958,

No Drawing. Original '3 plication Oct.

613,796. Divided and this Ser. No. 761,276

2 Claims. (Cl. 260-18) A non-exclusive, irrevocable, royalty-freelicense in the invention herein described, for all governmentalpurposes, throughout the world, with the power to grant sublicenses forsuch purposes, is hereby granted to the Government of the United Statesof America.

This invention relates to the preparation of paint and varnish vehicles.More particularly the invention relates to the preparation of paint andvarnish vehicles that possess built-in fungicidal properties, that is,in which the fungicide is chemically bound to a filtn-forming componentof the vehicle. Built-in fungicidal properties are attained according tothe process of this invention by integrally incorporating, as thefungicidal moiety, certain organic compounds, such as, tripropionin orundecyclenic acid by ester interchange, or hexachlorocyclopentadiene byDiels-Alder adduction in a conventional tung oil vehicle duringpreparation of the vehicle.

It is a well recognized fact that conventional paint and varnishespossess little or no resistance to the action of fungi. Therefore, asone means of attaining some semblance of mildew resistance in protectivecoatings it is customary to incorporate, as a separate entity after thepaint or varnish vehicle has been prepared, some material (i.e. a heavymetal such as copper, zinc, mercury, lead or compounds of these elementsor organic compounds) which of itself possess fungicidal properties.Such a method is only moderately successful and is, for some purposes,undesirable. In the case of coatings con taining fungicidal componentsas additives, the fungicidal material is dispersed throughout thecoating with no real chemical bonding between the fungicidal additiveand the complex homogeneous organic mass that makes up the vehicle. Thismeans that fungicidal activity is limited to those particular portionsof the protective coating where the additive happens to be located. Theadditive, moreover, being a quite separate component insofar as thevehicle itself is concerned, is free to separate, migrate, ariddisappear entirely from the applied coating once the finished coatinghas been spread in a thin layer over the surface being protected. it isa well known fact that finely divided metallic mercury, for example, ischaracterized by an extremely high vapor pressure and in the case of its(mercury) presence as a finely divided additive in a protective coating,rapid loss by volatilization would be certain. Migration or loss byvolatilization, leaching, or mechanical abrasion constitute seriousdisadvantages in the case of organic fungicidal additives. The problemis best exemplified in the case of paint and varnish vehicles formulatedfor the purpose of protecting surfaces in the interiors of foodfactories. Humidity, temperature, and nutritional conditions in foodfactories are ideal for mold and fungus growth, but in these particularlocations, the use of paints that incorporate toxic components isclearly undesirable. A recently published statement concerning theproblem of fungicidal paint preparation is to be found in the AmericanPaint Journal for September 19, 1955, pages 80-90.

A primary object of the present invention is to provide States atent OPatented May 16, 1961 paint and varnish vehicles which have incorporatedin the vehicles themselves, as an inseparable constituent, an integralfungicidal component.

A typical paint or varnish vehicle without fungicidal properties may beprepared employing the following procedure:

One hundred parts of resin (i.e., a pentaerythritol ester of maleicmodified rosin) and 240 parts of a drying oil (i.e. linseed oil, varnishmakers grade) are heated together to about 585 F. and held at thistemperature until a requisite bodying (increase in viscosity) hasoccurred. The heated mass is allowed to cool to about 350 F. and thenthinned with mineral spirits to about 50% solids. Such a product withsubsequent incorporation of driers constitutes a varnish or such aproduct thinned following incorporation of a pigment and driersconstitutes a paint (enamel). Either product would not normally possessany fungicidal properties. As stated earlier, one method of gaining somesemblance of resistance to fungicidal attack in a conventional paint orvarnish vehicle prepared as described above would be to incorporate asan additive to the finished vehicle some heavy metal or the saltsthereof or some organic additive. This operation, of course, will giverise to the undesirable effects recited earlier.

We have discovered that paint and varnish vehicles that posses built-infungicidal properties can be prepared by integrally incorporatingcertain organic compounds, such as, tripropionin or undecyclenic acid byester interchange, or hexachlorocyclopentadiene by Diels- Alderadduction in a conventional tung oil vehicle during preparation of thevehicle. The fungicidal properties so produced are an inherentcharacteristic of the homogeneous mass that goes to make up the finishedvehicle. Furthermore, the built-in fungicidal properties will remain inthe homogeneous mass even after the vehicle is transformed into a paintor a varnish, applied to a surface, and finally develops into aprotective coating. Fungicidal activity in such a coating is ascontinuous as the coating itself and is not limited to isolated areas ofthe coating as is the case when fungicidal additives are put into apaint or varnish simply by mechanical mixing. Migration of thefungicidal entity within a paint film prepared according to ourinvention is impossible.

In general, in accordance with the present invention, paint and varnishvehicles that possess built-in fungicidal properties are produced byheating for the usual time and at the usual temperature required toproduce requisite bodying (increase in viscosity) a resin, drying oil,and/or drying oil fatty acids and tripropionin. Subsequent to heatbodying, the vehicle so produced can be mixed with any of the solventscustomarily used for thinning purposes in the varnish industry anddriers can be added. In the heat bodying operation, the procedures andapparatus customarily used in the paint and varnish making art toproduce conventional vehicles can be employed. The paint and varnishvehicles provided by this invention are unique in that the fungicidalcharacteristics have been incorporated into the finished homogeneousmass as an inseparable constituent, held by chemical bonding andtherefore not subject to removal from the homogeneous mass thatconstitutes the finished paint or varnish vehicles by volatilizat'ion,preferential attack by solvents, oxidation, or any mechanical processessuch as weathering or scrubbing. The following examples are illustrativeof the details of practicing the present invention.

EXAMPLE 1 A vehicle prepared by heating together 60 parts of a resin(Epon 1004), 20 parts of tung oil fatty acids and 6.5 parts oftripropionin for one-half hour at 425 F. gave tion. The rating withAspergillus aryzae was 3.8, with Aspergillus niger 4.0.

EXAMPLE 4 A vehicle prepared and tested'as in the above examples butwith tripropionin being replaced with 5 parts ofhexachlorocyclopentadiene produced a clear film dry to touch in /4 of anhour. The fungicidal properties of this vehicle were good. The numericalrating with Aspergillus oryzae was 1.5, with Aspergillus niger 2.5.

where 11:4, according to Shell Chemical Corporation TechnicalPublication SC:5446.

The standard testing procedure employed in all of the examples is asfollows: Whatman filter paper was coated on both sides with the testmaterial and allowed to dry for 48 hours; the filter paper was then cutinto 1% squares and ruled on all sides with India ink of an inch fromthe edge. Each filter paper square thus prepared was placed in a Petridish of nutrient agar; and the paper and agar subsequently inoculatedwith 1.5 milliliters of a suspension of spores of the test organisms.Three replicate dishes were used for each organism. The organisms wereAspergillus 'niger (ATCC #10535) and Aspergillus oryzae (ATCC #10196).The growth after seven, and after ten days was estimated numericallyaccording to the following key and the results of three replicate platesWere averaged.

Key

(1) No mold growth or any portion of the sample within the lined area.

(2) Slight mold growth on any portion of the sample within the linedarea.

(3) Moderate mold growth on any portion of the sample within the linedarea.

(4) Heavy mold growth on any portion of the sample within the linedarea.

The vehicle prepared as described under Example 1 showed fungicidalresistance according to the above key with Aspergillus oryzae of 1.5,with Aspergillus niger 2.6. This is good protection.

EXAMPLE 2 A vehicle prepared and tested as in Example 1 but having only2.5 parts of tripropionin rather than 6.5 as in Example 1 showedconsiderably less fungicidal protection. According to the key fungicidalresistance to Aspergillus aryzae 2.3, to Aspergillus niger 4.0.

EXAMPLE 3 A vehicle prepared and tested as above except with notripropionin showed practically no fungicidal protec- EXAMPLE 5 Avehicle prepared and tested as in Example 1 but with tripropionin beingreplaced with 14 parts of undecylenic acid produced a clear film dry totouch in of an hour. The fungicidal properties of this vehicle werefair. The numerical rating with Aspergillus oryzae was 3.0 after 10days.

EXAMPLE 6 A vehicle prepared and tested as above but containing only rawtung oil 25 parts and linseed oil parts as ingredients showed nofungicidal protection at all. The numerical rating with Aspergillusoryzae 3.3, with Aspergillus niger 4.0.

This application is a division of application S.N. 613,796, filedOctober 3, 1956, which issued as Patent No. 2,884,330.

We claim:

1. A fungicidal paint and varnish comprising, as the film-formingcomponents thereof, the composition obtained by heating together amember of the group consisting of a drying oil, drying oil fatty acids,and mixtures thereof, hexachlorocyclopentadiene, and a film-formingresin containing hydroxyl groups reactive with the acid groups of saidmember of the group consisting of a drying oil, drying oil fatty acids,and mixtures thereof.

2. A fungicidal paint and varnish comprising a thinner, a drier, and, asthe film-forming components thereof, the composition obtained by heatingtogether a member of the group consisting of a drying oil, drying oilfatty acids, and mixtures thereof, hexachlorocyclopentadiene, and afilm-forming resin containing hydroxyl groups reactive with the acidgroups of said member of the group consisting of a drying oil, dryingoil fatty acids, and mixtures thereof.

References Cited in the file of this patent UNITED STATES PATENTS2,667,463 Jakob et al. Jan. 26, 1954 2,771,479 Bloch Nov. 20, 19562,779,701 Robitschek et al Jan. 29, 1957 2,863,848 Robitschek et al.Dec. 9, 1958

1. A FUNGICIDAL PAINT AND VARNISH COMPRISING, AS THE FILM-FORMINGCOMPONENTS THEREOF, THE COMPOSITION OBTAINED BY HEATING TOGETHER AMEMBER OF THE GROUP CONSISTING OF A DRYING OIL, DRYING OIL FATTY ACIDS,AND MIXTURES THEREOF, HEXACHLOROCYCLOPENTADIENE, AND A FILM-FORMINGRESIN CONTAINING HYDROXYL GROUPS REACTIVE WITH THE ACID GROUPS OF SAIDMEMBER OF THE GROUP CONSISTING OF A DRYING OIL, DRYING OIL FATTY ACIDS,AND MIXTURES THEREOF.